Merging and Duplicate Suppression

Merge Another Topic Map

Suppress Duplicates

By default, the Omnigator does not suppress duplicate names,
occurrences, and associations when loading a topic map. If you
want to make sure that your topic map does not contain any such
duplicates, click on the button below.

This page allows you to merge another topic map with the current
one (xmltools-tm.xtm) or to suppress any duplicates
that it might contain. To merge another topic map, select it from the
box on the left and click the Merge button. To remove duplicates,
click on the Suppress button.

Principles of Merging

When merging topic maps, the goal is to ensure that multiple topics
representing the same subject are merged into a single topic. When two
topics are merged, the resulting topic should have the union of the
"characteristics" (names, occurrences, and association roles) and
other properties (e.g., subject identifiers and source locators) of
the original two topics.

Establishing Identity

There are various ways in which an application can determine whether two
topics represent the same subject. Two of these are defined in the Topic
Maps standard: Subject-based merging and Name-based merging. (Other
methods, such as the uniqueness of other properties, e.g. email
addresses, are currently left up to the application.)

Subject-based merging is the most robust method: If two topics have
the same subject identity (specified using <subjectIdentity>
elements in XTM), they must be merged. The Omnigator always performs
subject-based merging.

Duplicate suppression

During merging, duplicate properties that arise as a result of the
merge will be removed automatically. Duplicates in the source topic
maps will be treated in accordance with the settings for performing
duplicate suppression when loading a topic map. The default is for no
duplicate suppression to be performed. (This allows the Omnigator to be
used as a debugger and also speeds up loading.) The default can be
overridden by modifying the 'duplicateSuppression' properties in the
file 'tm-sources.xml'.